Gypsum (calcium sulfate) panels are commonly used as sheathing panels in wall, door, floor, ceiling, roof, and other building applications. Lightweight gypsum panels are desirable for construction applications, for easier handling and installation. However, these lightweight boards should be manufactured to experience minimal loss of strength and integrity as compared to traditional boards.
Currently there are two known methods to manufacture lightweight gypsum boards. The first involves introducing a foaming agent into the gypsum stucco slurry to form bubbles in the gypsum board. This method often results in inconsistencies in foamed bubble size and bubble density in the board, due to process factors that are difficult to control, such as the timing of foaming initiation, the temperature of the slurry, and the pH of the formulation. This inconsistent bubble size can result in uneven density throughout the board and thereby diminish the strength and integrity of the board.
The second method involves incorporating hollow microspheres into the gypsum stucco slurry to decrease the density of the resulting board. However, this method can result in uneven density throughout the board and layer separation, for example due to the packing density of the microspheres being much lower than the slurry, resulting in diminished strength and integrity of the board.
Accordingly, there is a need for improved lightweight calcium sulfate composites and methods for their manufacture.